The Bosch BAT622 battery is the lightest, most compact and longest runtime FatPack-style battery available in the power tool industry. CoolPack™ heat-conductive housing is specifically designed to cool internal cell temperatures for 100% longer recharge life. The battery is compatible with the complete line of 18V Lithium-Ion power tools. The Bosch BAT622 battery is built with advanced technology high-capacity, low-resistance Lithium-Ion cells. BAT622 batteries maintain the same size and weight footprint found on previous Bosch 3.0 Ah, 4.0 Ah and 5.0 Ah 18V options.